[TowerTalk] how do you model a hairpin match?

[StellarCAT]

Ok.... I read the Antenna Handbook... it says to use a chart they have – reading it at 52 ohms line impedance (coax)... and 22 ohms RL I need 42 ohms of reactance. 
Then shorten the driven element to produce enough capacitive reactance to cancel out the inductive and transform the impedance up to 52 ohms. 

So I enter 42 ohms as a center load in my driven element (6ft/-6ft length load set to 50% and is 50% ... ) ... then shorten the length of the driven element. But this doesn’t work. The load never gets transformed. 

What I’ve been doing is enter their length/diameter info from their manual... then adjust the driven element to get the SWR where I need it (centered) ... then I read the load resistance off the SWR chart and change the “alternate’ source impedance to be this value. Finally I add in just enough hairpin to cancel out any capacitive reactance. This works – I get the same SWR curves that are published by M2 when I model their antennas... so I know its ‘right’. But I can’t seem to now NOT use the ‘switch’ to a different line impedance in order to determine the correct hairpin XL so I can figure out how to build the hairpin! 

any one see what I’m doing wrong please?

This is using EZNEC5

Gary 
K9RX